Improvement in relief-valves for air-brakes



.s. R. KNEELAND.

RELIEF VALVES FOR AIR-BRAKES.

No. 190,223. Patented May1,1877.

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} UNITED STATES SY-LVANUS R. KNEELAND, OF BOSTON, MASSACHUSETTS.

IMPROVEMENT IN RELIEF-VALVES FOR AIR-BRAKES.

Specification forming part of Letters Patent No. 190,223, dated May 1,1877; application filed March 2, 1877.

To all whom it may concern:

Be it known that I, SYLVANUS R. KNEE- LAND, of Boston, in the county ofSufl'olk, State of Massachusetts, have invented certain new and usefulImprovements in Valves, of which thei'ol lowing is a descriptionsufficientl y full, clear, and exact to enable any person skilled in theart or science to which my invention appertains to make and use thesame, reference being had to the accompanying drawing, forming a part ofthis specification, in which-'- Figure -l is a view of the valvedetached from the case; Fig. 2, a vertical longitudinal section, andFig. 3 a side elevation.

Like letters of reference indicate corresponding parts in the difi'erentfigures of the drawing.

My invention relates to that class of valves which are employed inair-brakes for railwaycars; and consists in a novel construction andarrangement of the parts, as hereinafter more fully set forth andclaimed, by which a simpler, cheaper, and more efl'ective device of thischaracter may be produced than is now in ordinary use.

1n the drawing, A represents the case or body of the valve; D, thescrew-cap forming the head nextthe cylinder of the brake; (J, thescrew-cap forming the head nearest the locomotive when the valve is inposition.

The lower portion of the case is thickened, and through the thickenedportion there is a hole, 6, connecting the interior and exterior of thecase. The thickened portion of the case is leveled or planed on itsinterior surface to form a seat for the sliding valve J. This valve hastwo semicircular vertically-arranged heads, F F, each being providedwith a series of perforations, g g, the head F hav ng also ahorizontally-projecting cylindrical arm, K.

Beneath the body of the valve J there is a plate, H, fitted to slidelaterally between the lower sides of the heads F F, as seen in Fig. 1.This plate has an upwardly projecting stud, I, which is fitted to workin an aperture (not shown) in the body of the valve J, the aperturebeing considerably larger than the stud to permit free movements of theplate.

In the use of my improvement, the valve J, with its plate H, is insertedin the case A,

the arm K projecting into the neck B of the cap 0, as shown in Fig. 2.Air being now let in through the neck B, to apply the brake, will causethe. valve J to slide on its seat, the plate H closing the hole 0, theslide continuing to advance until it strikes the packing-ring Ll betweenthe body A and cap D. The air on its way to the cylinder will now passthrough the holes 9 g, the aggregate area or capacity of which is equalto that of the neck m.

In letting off the brakes when the pressure is removed suddenly, theexpansive action of the air in the cylinder will allow it to returnthrough the neck m, causing the valve J to slide toward the head O, andopening the hole 6, through which the air will escape, the neck B, atthe same time, being closed by the arm or projection K.

The valve J, sliding freely on its seat, is easily moved by the impactof the air, entering the case A, either on its way to or from thecylinder; hence it will be seen that in applying the brakes theeduction-aperture 6 will always be instantly closed without interferingwith the passage of air through the valve via the holes 9 g and neck mto the cylinder. It will also be obvious that in letting oil the brakesuddenly,'the pressure being removed from the air passing through theneck B, the expansion of the air in the cylinder, re-

acting against the head F through the neck m, will instantly close theneck B by means of the arm K, at the same time opening the hole 6; butwhen the brakes are let ofl' gradually at the engine, the valve J willnot be moved from the head D, or the hole 0 opened, but the air willpass from the cylinder gradually through the holes 9 g, thus relievingthe brake without tripping the valve-a very essential feature of myinvention.

, The object of the plate H is to provide 'a perfect means of closingthe hole 6 in case the valve J is raised or partially turned by theaction of the air against its heads F F.

It will be understood that as the valve is moved toward the neck m, whenthe head F comes into contact with the packing-ring l beneath the cap D,there is sufficient space between the head and cap to allots the air topass freely to the neck, and through it to the cylinder; and that, whenthe head F is in PATENT Series.

contact with the packing-ring l beneath the 2. The combinatiomwiththecaseA, having cap 0, air cannot pass through the neck B, port 6, andcaps O D, neck B, and plate H, but may escape from the cylinder throughthe 0f the valve J, having the arm K, substanhole a. tially as and forthe purposes specified.

Having thus explained my improvement,

what I claim is--. v SYLVANUS R, KN EELAND. l. The c0mb inati0n,'withthecase A,'hava A I i l ing port e, and caps O D, and valve J, 0011-Witnesses:

structed substantially as described, of the, .H. E. METGALF,

plate H, substantially as and for the purpose G. M. HENDRIOK.

specified.

